To investigate the intrinsic mechanism of alternative splicing (AS) participated in drought tolerance in plants, the effects of macrolides pladienolide B (PB, one of the AS inhibitors) were studied using the phosphoenolpyruvate carboxylase (C4-PEPC) rice (PC) and “Kitaake” (WT) rice lines in pot experiments and hydroponics experiments, respectively. The changes of photosynthetic parameters, total soluble sugar and sugar components contents, some main antioxidant enzyme activities and antioxidant contents, Ca2+, NO, H2O2, ABA contents, transcript levels of sucrose nonfermenting-1 (SNF1)-related protein kinases (SnRKs), arginine/serine-rich proteins (SR proteins), and PEPC both in C4 and C3 type of the functional leaves in rice lines were measured. Agronomic traits of the WT and PC were recorded in the mature period. In pot experiment, compared with the natural drought treatment alone, the treatment of 0.5 µmol L-1 PB with drought at booting stage had a significant decline on agronomic traits of the tested rice. Among them, plant height, panicle number per plant, filled grain number per panicle, and grain yield per plant in PC were significantly higher than those of WT. In the hydroponics experiment with 0.5 µmol L -1 PB combined with 10% mmol L-1 polyethylene glycol 6000 (PEG-6000) to simulate drought stress, compared with PEG treatment, net photosynthetic rate, relative water content, total soluble sugar content, proline content, SOD activity, POD activity, CAT activity, and PEPC activity were significantly increased in PC than those of WT. Similarly, the contents of sucrose, glucose, fructose, and Ca2+ of leaves in PC lines were significantly higher than those of WT. It was noteworthy that the relative gene expression levels of C4-PEPE, Osppc2a, SnRK2s (SAPK8 and SAPK9), SnRK1s (OsK1a, OsK24, and OsK35), and SR proteins (SR33, SR40, RS29, RS2Z21, and RS2Z38) under PEG+PB treatment were significantly lower than those under PEG treatment. It was further verified by using 10 mmol L-1 EGTA experiments [Ethylene glycolbis (aminoethylether)-tetra-acetic acid, a chelate solution of calcium ions] that Ca2+ were involved in the drought response by regulating the transcript levels of SR proteins genes in rice. In addition, the Ca2+ content in PC lines was significantly correlated with soluble protein content, ABA content, and RS33 transcript level, respectively. In conclusion, AS participated in drought response by regulating the expression of SR related genes through sugar signal both SnRK1s and SnRK2s, and calcium ion as well, which played a positive role in drought tolerance in rice. Compared with WT, PC had a stronger positive effect, which was closely related to its high endogenous Ca 2+ content and the contents of sucrose, glucose, fructose.